Sand-Glass—(Clepsammia)—A dumb-bell-shaped glass globe containing sand, and with a small aperture through which the sand flows in a certain fixed time. The most common form is the hour-glass but many others are in use as the three-minute glass for boiling eggs, the two-minute glass used by the British Parliament, etc. Dried and finely powdered eggshell sometimes used in place of sand. The principle is the same as that of the simplest form of clepsydra. See [Hour-Glass].
Sandoz and Trot—A firm which established the first watch factory in Switzerland in 1804. Previous to that time watchmaking had been a house industry.
Second—One-sixtieth of a minute: 1-3600 of a mean solar hour.
Secondary Compensation—Same as "auxiliary compensation." See [Auxiliary].
Seconds Hand—The hand on the dial of a clock or watch which revolves once a minute. Sometimes small and set in a small circle of its own. Sometimes long and traverses the whole dial. See [Center-seconds and Sweep-seconds].
Seconds Pivot—The prolongation of the fourth wheel arbor to which the seconds hand of a watch is fixed.
Seconds, Split—Divided seconds—into quarters, or fifths; measured by a chronograph.
Shadow—A darkened space resulting from the interception of light by an opaque body.
Shagreen—Made from the tough skin that covers the crupper of a horse or ass. Rough seeds are trodden into the skin and then allowed to dry. The seeds are shaken out and the skin dyed green. Then the rough surface is rubbed down smooth leaving white spots on the green ground. Also made from the rough skin of sharks and dolphins. Formerly used a great deal for the outer cases of watches. See [Pair Cases].